Television transmission system



April 23, 1935. w. A. TOLSON 1,998,644

TELEVISION TRANSMISSION SYSTEM Filed July 16, 1930 INVENTOR: l8 77mMsn/rrm' lam ATolson,

' BY J -L i -z/ S HIS ATTORNEY.

Patented Apr. 23, 1935 I 7 I .UNITED STATES PATENT oFFlcEf TELEVISION TRANSMISSION SYSTEM William A. Tolson, Erlton, N. J., assignor, by mesne assignments, to Radio Corporation of vAmerica, New York, N. '.Y., a corporation ,of

Delaware Application July is, 1930, Serial No. 468,221

3 Claims. (01. 178-6) My invention relates to improvements in te1e- More particularly in'accordance with my invision transmission systems. I vention, suitable switch means are associated In using the conventional indirect or so-called with an electrical circuit forming part of a telespoti scanning system for television transmisvision transmission system and are operable to sion, it has been proposed, heretofore, to employ render the same ineffective for transmission, the 5 a lens-turret, inassociation with and forming lens-turret forming part of the scanning appart of the scanning apparatus, which includes paratus, which includes the usual scanning disc the usual scanning disc or discs, to provide'for or discs, being so co-related with the switch rapid and convenient change or adjustment of means that the latteris controlled in accordance the system for scanning objects located at difwith the rotary movement of the turret in ad- 30 ferent distances therefrom, or for varying the justing the scanning apparatus for objects at difscanned area of an object'at substantially a fixed ferent distances therefrom. V distance from the apparatus to give the effect 'My invention resides in the system and apof the object being different distances from the paratus of the character hereinafter. described apparatus as determined by the area scanned. and claimed. .1.) The turret referred to carries a number of dif- For the purpose of illustrating my invention, ferent lenses or lens systems which are moved one embodiment thereof is shown in the drawselectively into operative position with respect ing, in which j to the associated disc or discs of thescanning Fig. 1 is an elevational view,partly diagramapparatus upon rotation of the turret, the respecmatic, of a system embodying my invention; I Q0 tive lenses or lens systems being effective to Fig. 2 is' an elevational view, looking: toward adapt the transmission system to different operward the left in Fig. l; and i ating' conditions, such, for example, as would Fig. 3 is a fragmentary view similar to Fig-1, be required to satisfactorily scan objects at illustrating a modification; I

widely varying distances from the system. As The reference numeral l0 designates a lens- 25 the lens-turret is rotated from one position to turret, of well-known construction used in scananothenin the various constructions used'herening apparatus for a television transmission systofore, a very unpleasant condition develops at tem, and includes a base member ll supported the receiver for the reason that the'picture is for rotary movement aboutan axis. [2 and carplaced completely out of focus as one'lens is rying a plurality of different lenses or lens sys- 30 moved out of operating position and is again terns [3,14, 15, and IS, the latter being moved brought back into focus as another lens is moved selectively into operative association 1 with the into operating position. other parts-or units such, for example, as the With the foregoing in mind, one of the objects usual scanning means herein conventionally illusof my present invention is to provide an improved trated as a disk 23 of the Nipkow type provided 35 television transmission system wherein the same with a series of spirally arranged apertures 24. is rendered ineffective for transmission upon When the various lenses forming the lens system movement of the lens or other structure to adapt are moved into cooperative association with the the system to different operating conditions such scanning disk element, for example, these various 4 as that of distance of the object from the 'scanlenses are effective to adapt the system for scan- 40 ning apparatus. ning objects at different distances therefrom.

In accordance with my invention, suitable A photo-cell amplifier of any suitable construcmeans are provided for rendering thetelevision ,tion, and which includes the usual B battery ll transmission system ineffective for transmission, and forms part of the television transmission such means operating automatically for this pursystem, is indicated generally by the reference pose upon movement or adjustment of the means niuneral It. A switch IQ of any suitable conor structure provided for adapting the system to struction is connected as shown in the battery different operating conditions. circuit, the arrangement being such that when Further in accordance with my invention, a the switch is closed such circuit is completed,

television transmission system is automatically and the system effective for transmission. As 50 rendered ineffective for transmission upon disis well known, when switch I!) is open, the system placement of the lens structure associated with will be ineffective for transmission. I the scanning apparatus in adapting or adjust- A plurality of pins 20 are carried by the base 7 ing the same for scanning objects at different ll of the turret and are disposed for engagement distances therefrom. with the switch l9, as shown in Fig. 1, to close 55 ring disc or discs of the scanning apparatus of which such lens then forms a part. The action is, therefore, such that the system is effective for transmission only when the turret has been rotated or displaced to place one of the lenses in operating position.

Upon displacement of any lens, or more specifically, upon rotary movement of the turret to change from one lens to another to adapt the system for scanning objects at;difierent distances therefrom, the pin 20 which previously engaged switch l9 to hold the same closedjis moved out of engaging relation with the same to permit opening thereof by its own spring action. The system is then ineffective for transmission.

From the foregoing it will be seen that the present improvements provide that during change or adjustment of the system to adapt the same to difierent operating'conditions, the system is controlled in such manner as to eliminate any undesirable effects or influences which might otherwise develop during such change, the system being automatically restored for normal operation when the desired change has been effected.

'While the present system or apparatus disclosed as representing one embodiment of my invention is, specifically, a structural arrangement for rendering the same ineffective for transmission by controlling a photo-cell amplifier forming part of the system, such control being made during change or adjustment from one lens .or lens system to another inthe scanning apparatus, it is to be understood that my inven- .tion is of much broader'adaptation, the broadest aspect being automatic control of a television system in any desirable manner during change or. adjustmentthereof for the purpose of adapting the same to different operating conditions, the, said control providing for elimination of undesirable effects which might otherwise develop during such Zchange or, adjustment.

In the specific embodiment of my invention disclosed, it is to be understood that various changes might, bermade without departing from theswitch operating to open the same and thus to render the television system "effective for lens elements usable individually for focusing the subject upon the scanning system, and means cooperating with the lens turret for rendering the scanning system operative only at time periods when one of the series of lens elements is in operative relationship with respect to the scanning system.

2. In'television transmission apparatus, a scanning system for converting light values on succes's'ive elemental areas of a subject of which an electro-optical image is desired into proportional electrical representations thereof, a lens turret associated with the scanning system, said lens turret comprising a base member supported for rotary movement and including a plurality of individual lens units each of a difierent focal length 'supported parallel to'the axis-of rotation and disposed concentrically about said axis for movement into'andput of operating association with the-scanningmeansso as'to focus the optical image thereupon, and means cooperating with the lens :turret for rendering the scanning system operative'only at time periods when one of the series of individual lens-elements is'in operasystem-so as to focus the-optical image of the subject thereupon.

3. In atelevision transmission system,-.-a scan- 'ning system for developing picture signals-a lens turret comprising a series of individual lensunits each of different focal 'length and each individually cooperable' with-said picture signal developingmeans to'form a'componentpart thereof, means forefiecting relative movement between the lens units and the picture signal developing means to render the latter effective selectively to-producesignals of subjects located at diiferent distances therefrom, and means operable to render the picture signal developing system ineffective for transmission during time periods withinwhi'ch different units of-the turret "are being placed in--cooperativerelationship with respect to the scanning means.

"WILLIAM' A. TOLSON. 

